Predicting persistent pain following endodontic treatment within the National-Dental-PBRN [presentation] Presentation uri icon


  • Objective: Persistent pain following root canal therapy is poorly understood. This study assessed predictive factors to better understand how persistent pain develops. Method: The outcome variable was persistent pain at 6 months post-obturation. It was defined as pain occurring =1 day during the prior month at levels =1/10 numeric rating scale. Sixty-one baseline patient and dentist variables were measured as potential explanatory candidates for this pain outcome. Using ordinary least squares regression modeling, the variance inflation factor (VIF) of each predictor was computed to detect multicollinearity; predictors with VIF >5 were not retained. The logistic regression model with stepwise selection methods (p<0.1) was performed to determine the association with the pain outcome at 6 months. Measures of association were expressed by odds ratio with 90% Wald confidence intervals. Age, gender, geographic region, and practice status (general practice versus specialty) were forced into the model, i.e., not subject to “entry/stay” criteria. Result: Of the 708 enrolled patients, 651 (92%) provided 6-month follow-up data and 65 (10%) met pain criteria. A total of 440 patients had complete data for all study variables. Starting with 56 eligible predictors plus the 4 forced variables (1 variable caused non-convergence and was not included), 7 remained in the final model. The efficacy of the final model was confirmed by goodness-of-fit test (p=0.27). The forced predictors were: age (OR=0.99, 90%CI=0.97-1.02; p=0.65), female gender (OR=1.49, 90%CI=0.82-2.71; p=0.27), region (5 regions; p-value for any difference =0.16), practice status (OR=1.20, 90%CI=0.67-2.16; p=0.61). The three predictors meeting criteria were: number of days in pain at baseline (OR=1.27, 90%CI=1.11-1.45; p=0.004), pre-treatment fear (OR=1.97, 90%CI=1.10-3.55; p=0.057), and subject’s baseline expectation of less-than-ideal outcome (OR=2.24, 90%CI=1.31-3.84; p=0.01). Conclusion: Baseline pain duration, fear, and expectations best predicted the occurrence of persistent pain at 6 months following root canal therapy.